1. Field of the Invention
This invention relates to a method for removing fluorine from fluorine-containing wastewater, more particularly to a method for removing fluorine from fluorine-containing wastewater using a fluorine-reactive agent that can react with fluorine ions so as to form sodium aluminum fluoride.
2. Description of the Related Art
Conventional wastewater treatment for fluorine removal involves addition of a fluorine-reactive agent, such as CaO, Ca(OH)2, CaCl2, into the wastewater and reaction of the fluorine-reactive agent with fluorine ions in the wastewater to form CaF2 precipitate, which is subsequently removed from the wastewater.
The conventional treatment method is disadvantageous in that addition of powdered CaO or Ca(OH)2 into the wastewater tends to release dust into the environment during operation, which is harmful to operators. In addition, the solubility of the powdered CaO or Ca(OH)2 is relatively low. As such, an excessive amount of the powdered CaO or Ca(OH)2 is required. Moreover, Ca(OH)2 precipitate is also formed during precipitation of CaF2 in the wastewater. As a consequence, a large portion of the cake thus formed contains undesired water and Ca(OH)2, which cannot be recycled.